What is it?
InMaps is a tool provided by the team at LinkedIn Analytics which produces a map of your connections on LinkedIn - see here for more detailed information on what it is and how to use it.
How do you use it?
Just follow the instructions provided - you'll need to login to LinkedIn and give access to the InMaps application to access your LinkedIn data. Once the map has been built, you can zoom and pan to inspect your connections, and also assign labels to the colour coded groups. Click on any connection to highlight your shared connections.
Note that if you have a secure scripting environment, you'll need to allow scripts from both linkedinlabs.com and yahooapis.com
Why is it Useful?
Suppose you are looking for connections which might allow you to reach out to a company as a potential client. You can use LinkedIn to show you people within that company who are second or third level connections, which is very useful. However, if you have the fortunate situation where there are several routes in, it pays to know who is connected to who.
For example, looking at AliceCo, you see that there are two employees there who are second level connections, Bob and Claire. You are connected to Bob through David, and to Claire through Ellie and Frank.
Hence you might try to approach Bob via David, or Claire via Ellie or Frank. However, if you know that Ellie and Frank used to work together, that would be your preferred route in, as it has more "weight".
Mapping out your connections allows you to see these useful interconnections, most of which you'll know about, some of which you won't and these are the ones which can be useful. Looking at my map, three of the interconnections are surprises - I had no idea that the people concerned knew each other.
LinkedIn has an option to disallow access to your data from third party applications, however so far as I am aware, InMaps does not count as a third party application and so this setting should not cause any problems.
LinkedIn will always show shared connections, so setting your account to not show connections to anyone other than yourself also should not cause a problem.
The InMaps FAQ points out that the data used to prepare maps is only updated on Sundays, so you'll need to wait to see your new connections appear, I normally look at mine on Mondays to catch up.