Staff face dismissal for criticising their employers in chatrooms and blogs, report Phil Baty and Tony Tysome.
Academics' internet activity is increasingly being "spied on" by managers, it was claimed this week after a lecturer at Wolverhampton University was sacked for making a series of allegations online.
Union leaders and academic freedom campaigners argued this week that lecturers and researchers must be free to criticise their managers and to discuss their jobs without fear of reprisal.
But university marketing chiefs warned that online activities such as blogs and web forums are increasingly being monitored by universities keen to protect their reputation.
The debate was sparked by the case of Sal Fiore, a senior lecturer in computing at Wolverhampton. An investigation by The Times Higher has established that he was sacked on grounds of gross misconduct last month following a series of e-mails.
Evidence against him included a posting he had made to a discussion forum in which he named Wolverhampton in association with general bullying allegations.
Dr Fiore had also contributed to a blog for bullied academics - bulliedacademics.blogspot.com - where academics this week complained that they were under surveillance.
One said that managers use postings "to 'get' their targets on some violation of university policy". Another said that bosses were "snooping around, looking for 'evidence'".
Sally Hunt, general secretary of the University and College Union, said:
"Academics should not be made to feel that any comment they make may be picked up by some sort of university spy team and used against them."
Peter Reader, director of marketing and communications at Bath University, said that there was "huge interest" in such websites and that universities were beginning to monitor them.
Wolverhampton confirmed that Dr Fiore's dismissal related to a number of incidents. Geoff Hurd, deputy vice-chancellor, said: "No member of staff has been, or ever will be, dismissed for exercising their right to freedom of speech."