Quite often when you are shopping on checkout you are asked for your postcode or some retailers ask for your email address. However at a recent shopping expedition in a childrens clothing store I noticed a big assumption being made that might be a major marketing error.
The older gentleman in front of me was obviously buying some clothes for his grandchildren, but on checkout the cashier did not ask for his e-mail they just asked for his telephone number, yet when I checked out two minutes later she asked me for my e-mail.
This retailer spends a lot of resources and time marketig via e-mail and social sites, especially Facebook, yet the assumption was this Grandad did not use a computer. One of the fastest growing groups on Facebook are above the age of 55 - grandparents wanting to keep in touch with family will be part of that group.
The danger of making this assumption could also apply to your own personal brand. Don't assume that the people you are trying to reach are not using technology for other reasons and could also be reached by you - that also applies to making sure what you do and say online is appropriate, you never know who is reading it.