I finally found a fix to this very annoying problem with Linkedin (that Linkedin never solved by themselves ): Linkedin becomes so slow that pages never load (it seems that hundreds of people have this problem: link 1, link 2, etc..)
Linkedin must hide a tremendous amount of "technical expertise" for being the only website causing "internet protocol side effects" or whatever... Please note that this problem started in 2008.
The solution that worked for me is setting the MTU value to 1360 as described here.(dated 2010 feb.08) How to change the MTU value on window is explained here (I'm on WinXP).
But I'll keep an eye on it, because in the past many "solutions" seemed ok but lapsed only few hours.
Thank you, linkedin ....