BrowserToolbar is an IE toolbar object which comes with various other components that act as adware and spyware.
ausvc (after the filename of one of its components), Backdoor.Autoupder (Kaspersky Anti-Virus), Downloader-W (McAfee), BrowseEvt (after the spyware component it installs), TROJ_SUA.A (Trend Anti-Virus).
Can be downloaded and installed from the manufacturer's site, but it more likely to come as an affiliate's drive-by-download (ActiveX install). BrowserToolbar is known to have been installed at least once by exploiting a security flaw in Internet Explorer.
Yes. Opens pop-up adverts.
Unknown. It has been alleged that the BrowseEvt component spies on URLs visited, but this was not working when I tested the software as the manufacturer's servers were not responding.
Yes. BrowserToolbar downloads and installs updates to all its components silently, without code-signing.
Unknown.
You could try the downloadable uninstaller from browsertoolbar.com. Alternatively Spybot S&D 0.95b6 and many anti-virus packages can remove it.
See the AV vendors' pages below for manual removal info.