Whether you've got a live public announcement that you're looking to hype, a big sale coming up at your store, or just about anything else you want to remind your site visitors about, NudgeMail--the company that makes what I believe to be one of the best inbox innovations in years--has a cool solution that's worth checking out.
The NudgeMail Widget is a simple Web form that you can fill out with a date, time, and description. It then spits out a chunk of code that you can embed on any site to remind visitors about your upcoming event. You can select either a graphical button widget or a simple link.
Once a visitor clicks on the link, it uses their email client to send a reminder request to NudgeMail, which in turn will trigger the NudgeMail servers to send out an email reminder at the appropriate time.
What I like about the NudgeMail widget is that it's an entirely opt-in way to reach your customers' inboxes without the expense and hassle of maintaining an email list. On that same score, however, it means you won't be building your own marketing list by using it.
I'd like to see NudgeMail take this idea further with a more customizable button that includes the actual title text of the event itself, because the provided code just creates a generic Remind Me button that requires users to do a lot more formatting of their own to make it look useful and coherent on a Web page. At the very least, I think the code should us a complete box that includes event and reminder information, and maybe even explains that this thing is going to send an email on the user's behalf. Otherwise, I can imagine angering users who suddenly see their email client leap into action when they click it.
Still, if you don't mind writing in your own explanation of what the button does on your site, the NudgeMail Widget strikes me as a very easy way to get site visitors to opt in for your reminders.