Wireframes are not enough
As at most web agencies here at Evoluted wireframing is an integral part of our design process. Every project first goes through a wireframing process to ensure that we build a robust, easy to use website that includes all the features and elements required. The final wireframes are used as a starting point by our designers and throughout the project life these are referenced by designers and developers alike.
I'm not going to talk about why wireframes are good because they are. Ian Brennan has covered the basics well in The Wireframe – All You Need To Know and Paul Boag covers it well in The 7 Wonders of Wireframes and Quick and Dirty Wireframes.
However we're increasingly finding that issues which should be identified during the wireframing process are not, instead we are catching them on the first or second revision of the site mock-ups.
This wastes time, resources and causes some furrowed brows from the designers who have to work out how to insert or remove elements within a carefully crafted design.
The problem we found was that clients just didn't understand the wireframes, they'd either transfix on the minute detail or didn't study the detail enough and signed the wireframes off without really understanding them.
A pattern soon became clear when we sat down and looked more closely at the wireframes we'd had issues with. The problem wireframes either hadn't been created in a client facing meeting or the client hadn't been taken through the wireframes in person or over the phone. It seems (understandably) that when clients are left on their own with a set of wireframes they shut down and approve what they don't understand (and are probably afraid to ask).
Since we identified this issue we've gone to great lengths to always take clients through wireframes, addressing any questions or concerns verbally. And the result? Fewer issues are creeping through the wireframing process and we have happier clients (and designers).
Wireframes aren't enough; they need to be used in conjunction with explanation and discussion of the issues. Don't just rely on email, do it over the phone or in person, you'll be better off for it.