eBay is locked in discussions with StumbleUpon about a deal to buy the bookmarking tool for around $75 million.

However, the deal is still not finalised and could collapse at any time, a source close to the discussions told Reuters.

Google and AOL have also been mentioned as possible buyers of StumbleUpon, which recommends websites, videos and photos based on your interests. StumbleUpon learns about what you do and don’t like by monitoring the sites you rate with a ‘thumbs up’ or ‘thumbs down’. Research firm, ComScore, has reported that the number of page views on StumbleUpon tripled between January and March.