Lifehacker.com shows how to use GMail as a bookmarking tool. Of course, it's easier to just use del.icio.us, but many GMail fans will love this trick.
First, drag this link to your browser's link bar (in Opera, you must right-click and save as bookmark; drag and drop won't work.):
Clicking GMail this! creates a mini-interface to GMail prepopulated with a link to the web page you are visiting, as well as any text you have highlighted on that page.
If you aren't already logged into GMail, the log-in screen is displayed. You must log in and then re-launch GMail this!
More about GMail this!
To get started, login to your GMail account and click on the “Create a filter” link next to the searchbar. You’ll need to setup the filter criteria so that GMail knows what emails you’ve tagged for bookmarking and what emails to leave alone.
To ensure that legitimate emails aren’t whisked away to join your bookmarks, you want to use your email address for both the To and From fields. That way you can be sure that your bookmarks can only be added by you. Then add your tag to the Subject field. For our example, we’re setting up a tag for your holiday wishlist, so add “wishlist” to the Subject criterion.
On the next page, you want to set the action that GMail will take when an incoming message matches the filter criteria you’ve created in the last step. First, so that your inbox isn’t full of bookmarks, check the “Skip the Inbox” checkbox. Now you can create the new label for your bookmark.
Now let's use this bookmarking style. From the page you’d like to bookmark, click the GMail this bookmarklet. Address the email to yourself, add your tag to the subject field, and send your bookmark. GMail will filter the email you sent into the label we set up earlier - in this case, Wishlist - and skip the inbox altogether. Just click on the Wishlist label in GMail to see all of your bookmarked pages. Need to send a couple of gift ideas home to the parents? No problem, just forward them a couple of your bookmarks!
While this system lacks the social aspect of other bookmarking systems like del.icio.us, it’s a quick and elegant way to integrate bookmarking into your GMail account.