They seem really attached to the idea that the data (or as they ponderously call it, 'the corpus') they have is very valuable. $9 million (with an impressive $2 mil/year burn rate) later they haven't figured out a way to extract any of that elusive value.
Browser bookmark sync is becoming a built-in feature in many popular browsers. Cross-browser support is an edge case that overlaps with the functionality of a number of web-based bookmarking services which generally offer a richer and more useful feature set than in-browser bookmarking.
In the period of about a week they've persuaded fewer than 30k of their users to maybe pay them $10/yr. This is probably not all that surprising given the above and the fact they've already announced that should they run into difficulties, they'll simply give up. Short of Stockholm Syndrome, it's hard to imagine why anyone would choose to rely on their service going forward, even if someone is foolish enough to buy them out.