Usability of Social Networks (LinkedIN)
One such network is LinkedIN. LinkedIN, for those that do not know is a social network to build and maintain professional contacts. The idea is simple. I know people, you know people, and these people know people, forming a network of associations.
LinkedIN is a good example of a social network web application. Here are some highlights (and a couple of dings):
GOOD: Low barrier to Entry
New people can be added to the system easily with only entering a couple of pieces of information. This allows the user base to grow and develop without full profiles.
This is generally one area where software development gets it wrong most of the time, looking at each user as a record, and each record should be as complete as possible, this makes the linkages of data easier for the programmer.
Unfortunately this creates a high barrier to entry where most potential contacts would bounce off and not be included in the network.
I recently began using this service, and I have a few people with only one contact (me) and only info about the associated company.
Making it easy to have incomplete records makes it easy to exploit these new semi-users in the future.
GOOD: Keeps the user informed about other contacts
LinkedIN also has a nice feature to show what your other contacts are up to. If a contact added a new connection, or recommends someone then it shows on your control panel, keeping you informed.
GOOD: System Status
There is a status area showing how complete your profile is. This allows you to take the next step in the process, making the record more complete. This makes the programmers happy and enhances the overall network. It also helps convert semi-users to habitual users by indoctrinating them slowly into the site.
GOOD: Graceful Security
The application will lock the user out after a pre-determined period of time. This has become standard for secure applications. What is not standard is doing it gracefully.
Many applications will time-out forcing the user to re-enter credentials and then either reset their session to the login point or take them to where they were last, losing their edits. The LinkedIN system is smart enough to retain your edits, log you in and then complete the process. Very sweet.
BAD: Editing Previously Entered Information is Difficult
While some of the entries have  links, many do not. In fact this is an instance where an edit link is detrimental to the user.
The edit link next to only the current contact (and not other contacts) makes the other contacts appear in-editable.
Other contacts are viewed in their completeness with edit links, but this is below the fold(you need to scroll to get there). Because of how the layout appears to have footer information (an ad to link out to your public profile on your personal website) giving the impression that there is no more information below that point.
By changing the  link to link to lower on the page, they could inform the user that these items are easily editable.
BAD: Tab Woes
The labels on tabs in the application can be a problem. While most are straight forward, the ones for the profile are confusing. Similar names do very different things. "Edit my Profile" is simple, and allows the user to edit the profile. The "Edit my Public Profile" gives the user the impression that they can have two distinct profiles, one for the public and one for friends/colleagues. This is not the case, this option simply allows the user to show and hide profile sections.
It would be better to call it something different, possibly profile preferences.
BAD: Profile Differences
Related to the tab woes is the way the profiles are displayed for your personal contacts and for you viewing your contacts.
The interface tabs change depending on who's details you are viewing. Keeping this consistent would allow the user to seamless jump between the two.
While not a big deal, it does add to some jumping about to see things like recommendations.
Social Networks in General
Social networking is akin to a video game where the user hunts for the prizes and adds them to his bag of goodies and continues to forage. LinkedIn propagates this by showing your contacts and your contacts contacts putting you in a virtual death match of adding to your network.
Social networks are the new version of the social club or local pub where you can keep in contact with others, if only virtually.