Thoughts on Linking

There are levels of linking on LinkedIn, as I see it. (Can you tell I got a puzzling invitation today?)

At the top are:

• people you actually work with (duh) or have worked with in the past
• friends, who you don't work with but who might know people at companies you're interested in, and vice versa

Next is the slightly dubious request, from:

• recruiters, who might have a valid reason for wanting to link, but don't specify
• people who work for the same company, but who you don't work with/don't know/have never met/live on another continent
• people who have "links" in common with you, but don't specify why they want to link to you (obviously this doesn't apply to anyone who modifies the form message to say "Jane Doe suggested that I contact you to talk about...")

More dubious still:

• people you don't know, who are in a different field, and give no reason for wanting to link (such as the self-employed geologist from Texas--really)

Am I missing anything?