Many Bookdog users have told me that they are beginning to use online social bookmarks storage services such as Yahoo's del.icio.us™ and Google Bookmarks™ instead of keeping their bookmarks on their hard drives. It makes sense, because while the biggest disadvantage of keeping data online is that you don't have it while you're offline, your bookmarks are generally useless while you're offline anyhow.
One's first thought is that reliability of an online storage service should be better, since these large corporations do a better job backing up data than 'the rest of us'. On second thought, however, many people are leery of storing data only on a free service whose Service Agreement clearly states over and over again that they owe you nothing and are not responsible for anything. (You do recall checking that little box, don't you.)
Control of your data is another issue. Anyone who's ever switched internet service providers has learned that it's better in the long run to have your own domain name. Likewise with social bookmarking; what's hot today may be not so in a year or two. And you may want to try out different services.
We started out with support for Google Bookmarks™ because there was nothing yet available for Mac users. With Bookdog 4.2, you can copy some or all of your bookmarks to Google™, learn how it works, and if you don't like it, copy 'em back, whenever you want to. It took an act of Congress to get cell-phone number portability a few years ago, but I'm happy to say that now bookmarks portability is available with a few clicks in Bookdog.
Finally, people get confused about what happens to all the folders they put their bookmarks in, and how these relate to the 'labels' they see in Google Bookmarks™ and the 'tags' they see in del.icio.us™. I didn't know either, so when I figured it out we wrote an article in Bookdog's Help to explain it.
Another article documents some other tips I've learned about Google Bookmarks™ that don't seem to be documented anywhere. I was going to call it Google Bookmarks: The Missing Manual, but I believe a book publisher out there has trademarked that.