With the likes of iterators I think it's a great thing, after all you don't want to care what the actual type of an iterator is, just that it behaves like you expect it to. It's duck typing but with the compiler verifying everything at compile time rather than forcing you to deal with runtime errors.

For the example you give, well I agree with you. But then foo is a local variable, likely it's lifetime is pretty short and it's type isn't as important as that it behaves as a vector-ish of strings. If your code specifically requires it to be a std::vector you can be more specific.

auto isn't necessarily meant to be used everywhere.

[edit] mouser beat me to saying much the same thing :)

Herb Sutter, Microsoft's head C++/CLI guy and author of the famous Guru of the Week columns, has nice little overview of some of C++11 new features over on this blog. It's really worth checking out.

The C++11 standard offers many useful new features. This page focuses specifically and only on those features that make C++11 really feel like a new language compared to C++98, because:

• They change the styles and idioms you’ll use when writing C++ code, often including the way you’ll design C++ libraries. For example, you’ll see more smart pointer parameters and return values, and functions that return big objects by value.
• They will be used so pervasively that you’ll probably see them in most code examples. For example, virtually every five-line modern C++ code example will say “auto” somewhere.

-http://herbsutter.com/elements-of-modern-c-style/