My understanding is that the more technically advanced solers might even have some automatic ways to get other boats speed and other information but for newcomers and not so technical people getting them can be time consuming and difficult.
Brainaid's sol toolbox has also the NMEA proxy which brings similar data from other boats as simulated AIS data to your computer. If you have the right navigation software installed you can see this data.
I have now added the other boats almost real time speed, course and wind data easily available to anyone interested in sollog. It can be educational to see how the top players sail and of course it's handy if you want to cover an opponent.
I was a bit uncertain first should I add this feature or not. It certainly reveals quite of a lot of information from the other boats. But when people in the race chat told me that similar information is already available I decided that it's probably more fair to have the data easily available for everyone.
Instructions how to see other boats data
The current data is showed only for boat lists, so you have to first define the names of the boats you are interested in seeing data from. For example for the Global Challenge Leg 3 which is currently running you can do that here (if you are reading this after that race has ended, you can't see any current data there as the boats are no longer sailing).
Type in the box name of the boat and click add. You can repeat this for all the boats you want and when ready click the "Latest data" (you can always come back to this page to add more boats later).
As an example you can look what the data looks like for the boats which were in top-5 when I was writing this.
You can then see the speed, heading, TWA, wind direction and speed of each listed boat. The data should be automatically updated every minute and it should be quite near the actual numbers the server is using. The data is calculated in the same way as you would do manually if you first estimated boats location & course from the client. Then do the same for the wind and estimate the speed from the polar information. The only difference is that the computer can do that same faster and with more detail.