Google Talk is a paradox in software: a minimalist, clean application, which unfortunately suffers from excess of those very qualities. Google has likely not given Talk much priority, hence it has always lacked features that other IMs like Yahoo, MSN etc. have. Common features like smileys, chat logging, video chat etc. are missing even today.
Get smileys and other features in Google Talk
Gplus is a Google Talk addon which brings functionality that is found in most other IMs (but lacking in G Talk).
- Chat Logging (in HTML)
- RTF (Rich Text Formatting
- Text filters to filter abusive words from conversations
GPlus official website is offline but you can download GPlus [Download.com]