Any time you install either new free software or a major upgrade, it's become typical for companies to "bundle" additional software with their own. During the install process it can be confusing, and some times software companies make it appear as if installing the additional software is a requirement of using their free software. This almost always isn't true, it just requires diligence when you go through the install process.
The key is that this bundled software is optional.
I've seen users zoom through the install process and check every box without reading the screens, and/or think that installing the bundled software is mandatory. Some software also has the optional bundled software "pre-checked" so again, if you don't pay attention you could install software you didn't want to.
There isn't anything wrong with installing the optional software, as long as you do so knowingly and willingly. The reason most free software developers bundle other well-known software with their own is because it's a source of revenue (they get paid by software companies to do this), and that helps fund the development of a product they are giving away for free.
This is a good thing, as long as you're aware of what's being installed on your computer. I've seen too many users who ended up with 10 browser toolbars, didn't know how they got them and blamed the browser for running slow. I've also seen Google Chrome installed on a lot of computers where the user had no idea how it got there. Some software changes your browser start page and could make other changes to your settings...all of which can be unsettling if you're not aware why it's happening.
My advice is simple: when you install or update software, slow down and read each screen. Know what you're agreeing to when you check a checkbox.
Here's a guide to installing the Avira update, with the assumption that you don't want to install the Ask.com toolbar. Always check the "Custom" install option. Typically if you check the "Express" the optional software will be installed for you. It's worth taking an extra 2 minutes to go through the options for the installation.
