@rv1974 said:
....If I already signed in to forum why do we need an extra authorization?.....
I suppose you are asking about the pluginstore at the website not the pluginstore plugin. In this case the reason is:
The sketchucation site uses PhpBB engine for the forums and Joomla CMS for all the other content including the pluginstore. They are bridged together so when you log in to one of them you're also logged in to the other one as well. A major factor for the performance of the Joomla side is the number of simultaneously logged in people. The more people are logged in at the same time the slower the Joomla part of the site becomes.
This slowdown is especially significant in case of more than about 50 000 simultaneously logged in users. To prevent this from happening we set a 6 hours timeout at the Joomla part of the site. It means that if you weren't active at the Joomla part for 6 hours you'll be automatically logged out from it while still logged in to PhpBB (forums). We'll try to find a solution for this at the new version of the site (under development). Until then when you remain inactive at the Joomla side of the site for more than 6 hours you need to log in again.
I hope the above answers your question.