The popular online personal finance forum, Askaboutmoney.com, has asked its users to change their passwords as a precaution after the site was hacked.
The Irish based site thinks its systems were breached around June 21 and that the hackers downloaded usernames and email addresses.
Founder Brendan Burgess says because of the way the site is constructed, it is thought that while the hackers may have been able to also access passwords, it is unlikely they would have been able to read them because they were protected.
The breach first came to light around the time of the hacking in June, and was fixed.
At that stage the administrators did not think personal information had been compromised.
However, suspicions were aroused further on Monday, after users of Askaboutmoney.com received spam emails to addresses which they had used to register for the service.
The emails were personalised to their Askaboutmoney usernames.
Although the site administrators do not think passwords have been compromised, as a precaution they have changed settings to force people to change their passwords if they have not already done so in the last 30 days.
They are also recommending that anyone who uses the same password with either the same username or email address on any other website change their passwords on those sites as well.
Mr Burgess says in the online post that he informed the Office of the Data Protection Commissioner about the situation on Monday afternoon and has received advice about how to proceed.
The site has apologised for the breach.