If you've been having issues with the Grand Theft Auto V Social Club or iFruit companion app, know that you are not alone. Rockstar has acknowledged that they are aware of certain problems tied to these two features, and have been actively working to resolve them.
Reported issues include account linking being down and stats not updating properly. When logging into the Social Club Site, some users report information like feeds/crews isn't loading right, and in the game, Snapmatic photos sometimes won't upload.
Regarding the iFruit app, Rockstar says they know about the login errors, endless loading spinners, and resetting data. iFruit was released just before Grand Theft Auto V came out, and basically lets users customize their vehicles, create license plates for the game, and play around with Chop the Dog.
A recent update on the Rockstar website notes that some of these issues should already be resolved, but the devs are still working on others:
Update for 9/18/13: We have made some changes that should help to resolve some of these issues, and will continue to work toward a full resolution for any remaining problems such as logging into iFruit
In the meantime, dig out Grand Theft Auto V Starter Guide, and connect with your fellow fans in the community.