“It seems that every time I start up my Mac I see an alert about application updates waiting for me. Some of them I don’t want. Is there anything I can do about shutting off these alerts?”
Yes. Start by launching System Preferences, selecting App Store, and disabling the Automatically Check For Updates option. Do this and the nudging stops. Of course it also means that you may miss out on some important updates. To help avoid that, you might create a weekly calendar alarm or reminder that reminds you to manually check for updates. You do that by opening that same App Store preference and clicking on the Show Updates button.
There are one or two things you can do within the App Store application. Launch it, click on the Updates tab, and locate updates that appear under the Software Update heading. Click the More link and then Control-click (right-click) on any updates that you don’t want. For example, printer driver updates that you’ll never use. A Hide Update command will appear. Select it and that update disappears. (You can make it reappear by choosing Store > Show All Software Updates.)
Regrettably this option isn’t available for all updates. Third-party updates will display no such command and remain in the list.
You also have the option to hide items in the Purchases tab – something you may want to do if you never intend to install an application that you purchased years ago. To do that Control-click (right-click) on an item in the list and choose Hide Purchase. (You can later unhide these items by choosing Store > View My Account, logging into your account, locating the Hidden Purchases entry, clicking Manage, clicking the Unhide button that appears next to each hidden application, and then clicking the Done button.
by Christopher Breen, Macworld