Typically, applications like Outlook or Vista Mail have very large limits on their address book sizes, while online services like Yahoo or Hotmail limit their address book sizes to 1,000 entries or less. Below are a few suggestions on how to manage your address book so that it remains below the 10,000 threshold.

Remove Duplicates
Large address books can be caused by accruing duplicate contacts over time. The Plaxo Premium Deduper is an address book optimizer which identifies duplicate contact information within your Plaxo address book and enables you to safely and easily delete or merge these contact entries. It also has the ability to remove duplicate calendar entries to help manage your Calendar. Click here to learn more.

Selective Folder Link
If you have over 10,000 contacts in your addressbook, chances are you have them organized into folders. You can select which folders to synchronize with your Plaxo Online using the toolbar's Synchronization Manager. The Synchronization Manager allows you to decide which folders to sync online and which folders to ignore. Click here to learn more.

Large Calendars
If your calendar program supports it, you can archive old calendar events or delete obsolete events altogether. As you continue to add more events to your calendar, its store size will grow. The bigger the store, the more things are negatively affected (slow display or refresh, search results, etc). Keeping the last 3 months plus all future events is typically good practice and should be enough data retention for most users.