HackingTeam is a firm in Italy, based in Milan. They produce vulnerability exploits, surveillance tools, and malware that they sell to "private" clients. Those "private" clients are typically governments, allegedly often oppressive ones (e.g. Sudan).
Yesterday HackingTeam has been hacked. 400GB of its data exfiltrated, and the infosec community is, I'd say, pretty happy about it. As you can imagine, HT did not have a very good reputation within the community.
It's interesting to compare te community reaction with the Kaspersky case. Kaspersky is a security firm that sells the notorious antivirus and does plenty of work on malware rev engineering and publishing. They discovered they have had an APT variant on their system for several month. Infosec community reacted with much sympathy, as it usually does in these cases.
Importantly, this hack may represent end of affairs for HT: depending on what will emerge from the data, many governments may become unhappy about the revelations. In particular, many "old clients" (and potential new ones) may decide to cut their commercial relationship with HT entirely.