TwitLonger will never post anything to your account without your knowledge and never follows, unfollows, changes or does anything else with your account.

So why are you asking to be able to do that?
Twitter offers three levels of permission:

• Read
• Read and Write
• Read, Write and Direct Message

Since TwitLonger needs to be able to send the link to your post to your Twitter account, it needs Read and Write permission. Unfortunately, this level is the same one that is used for following and unfollowing and updating your profile etc. TwitLonger never does these things. If there was a permission level to just send the Tweet with the link to your post, that would be the one used, but it isn't possible to just ask for that.

Services that do anything on your Twitter account without your permission are evil, nasty and deserve to be shut down. TwitLonger appreciates and respects the trust you put into the service when signing in with your Twitter account.