I think the first technological development, perhaps equivalent to humans developing language, will be methods to interfere with or cut the hive-mind into smaller clusters.
Because survival.
As a single group, as a single species, the hive-mind is, nonviable. Much of history has been, well, less conflict for the sake of conflict and more a struggle for resources. All people being equal (as your question has it) will simply mean everybody dies, when there isn't enough for everyone, and no mechanism to treat people unequally to decide who would go without, who would die for the others to have a better chance of survival.
Looking at hive species, ant colonies or beehives, two things are very clear - one is a very clear hierarchy, those crucial to survival (like, say, queen or other necessary-to-survival-and-reproduction individuals) are elevated above others who are merely drones... and so, when there is not enough for all, those expendable are sacrificed to maintain survival of the whole hive. Your human species has no queens, no way of designating essential-to-survival individuals, and any attempt to force unequal treatment of otherwise equal beings will lead right back to conflict and struggle.
This happened in humans, too, with some cultures giving most food to hunters (even if it means the sick, weak, or elderly die) because they have to be strong to get more food for everyone, other cultures privileging warriors (because being overrun by predators or outfought by competiton is the end), in other cases it might be healers, or wise-folk, or leaders, who got the nod as essential enough to be worth preserving at the cost of other lives. Though I guess, in a human body, we can't really sacrifice individual bits - oh, wait, we do. Sacrifice extremities to frostbite to protect the core, sacrifice fat cells and then muscles to starvation, to allow the major organs (heart, lungs, brain) energy enough to survive longer, throw up an arm to intercept a blow to the head or curl around tender organs to protect them at the expense of the sturdier musculature. No hierarchy means everything dies together, instead of some lasting long enough to find a way to survive.
The other thing that we see in hive species, that is missing here, is multiple colonies. Because a too large colony cannot sustain itself, and two colonies too near each other are in competition - its likely only one is going to win, and the other may not survive losing. If the distance the hive-mind can reach is practically infinite, then they will all act together - so there's no backup, no way for any survival of the species given any failure of the hive-mind. It would only take once for equal distribution of the food to leave everyone starving because hunters don't have enough strength to hunt or everyone vulnerable to predators because the warriors don't have the energy to fight, for the hive-mind to learn about the dangers. But, with only one hive-mind, well, it loses and there's no second chance to be had.
If the hive-mind survives those first, crucial failures - I expect it would be by physical isolation of a group/tribe/family, which was not close enough to distribute resources and starve together, or was not vulnerable to predators when they came, or something. So the hive-mind splits up into tribes, which are self-sufficient-ish, and physically separated so resources are not overtaxed.
Except then there will be competition for resources when tribes get too close, or too big, and unequal distribution, and those tribes closer or more individual (who can think of the survival of their tribe rather than the other tribe or the greater whole) will survive much better. Mental distance, not just physical, as a survival mechanism. And, thus, either natural evolution towards smaller distance/multiple hive-mind clusters, or the rise of mental technology (like meditation, probably, remember the parallel technology is language) that will let a fragment of the hive-mind slowly learn to cut themselves out, to close itself off from the greater whole for the survival of one tribe over another, or bring specific outsiders into a group for assimilation or expansion.
Thus my prediction that communication technology is going to be vital, even if in the opposite direction, interference rather than increased communication. Of course, once interference in the built-in hive-mind communication has been explored, technological adaptions may rise in significance again to bridge the new gaps.
Beyond that point, depending on the evolutionary triggers and mechanism of the ability, we might see either evolution towards a loose coalition of minds instead of total merge, that is, individuals (and then mostly human technological development), or towards discrete hives with adaptation towards classes of distinct, hierarchical roles. In the latter case, there is a small, outside possibility of one hive out-competing others too the point of, eventually, assimilating or eliminating any other hives.
If that happens, then we are nearly back to your original question
But, in this case, the hive would not be of individuals nearly identical to our own species, it would contain separate classes physically adapted to specific roles. This will have a not insignificant impact on how technology progresses.
I would expect somewhat slower or lesser use of domestication or tools for certain tasks, with the gap being filled with those classes or castes which were already adapted to those tasks. Each class or caste would probably develop its own technology nearly independently, since they are looking for things specialized for their own task rather than broad applications. It might be harder to initially cross-adapt discoveries or techniques, since each caste (and thus the hive-mind) will think of their discoveries only in terms of their own work - though once any cross adaption is discovered for a technique, other adaptions will probably spread rapidly across the whole hive as the hive-mind thinks about looking for any other possible uses.
Additionally, with the high value of specialization, I think the hive would be somewhat better at finding a single answer or solution to a problem or thoroughly investigating all variations of a tool or theory, rather than broader and more abstract discoveries or intuitive jumps. Still probably lots of both, but a bit more of a conservative lean and tending towards steady progression rather than large or luck-based jumps. Lots of people working in concert and with full knowledge of each other's work, instead of off on their own making all sorts of individual jumps and trying things others deemed unlikely, with unexpected success.
