I am sorry I have to be so explicit, I know most of you know what a solo is, but you would be surprised, there is always at least one person who thinks it's okay to put a mention in a long newsletter, at the end of a long article about something else, or add in links to other events/products in the email. Seriously, you woudln't believe how often! But I have tested it many many times, and solos with one topic and one type of link convert the best, and I want all speakers to get maximum exposure, which is why this is a requirement.