I successfully used the tizmos page with my students for a while, but there were a couple of issues with it. First of all, more and more of the links were not coming up with screenshots and instead had a message that due to increased traffic, there would be a delay. Well, after several weeks, the message would still be there! It kind of defeated the purpose of visual links.
The straw that broke the camel's back, however was that I read a post on Elementary Tech Teachers ning saying that tizmos was down because it had been hacked. Since I needed something for my kindergarten classes right away, I did some searching and found Only2Clicks. I found that it had a similar graphic interface and also had tabs, a feature that was not available on tizmos. The only problem was that it seemed at first that I had to enter the user name and password in order to get to the page, which was not a good solution for sharing with others. The other downside was that gave the students full editing capability, with one of them inadvertently deleting one of the links. After some searching around, I found that there is a URL to give out for a public page. I changed all of the favorite places in the bookmarks bar to the new link, both in the lab and in the kindergarten classrooms.
I did have an issue still where the cursor seemed to get stuck on one thumbnail, making it difficult to use the page. I contacted the developer and the problem was fixed within 24 hours.
Here is my Only2Clicks page. I add to it whenever I see the students. I use the tabs to separate the everyday links from the more distracting holiday links.