Oh, and just to make you aware, I have not added the client features yet. (I am planning to allow you to add clients so you can create invoices and print them or send them via email.) Cumulative daily totals are also created for the timestamp viewing page, but I have not pushed the hourly totals live yet.
There are many situations in which rewriting the entire codebase can destroy a project. I have seen it happen. People get excited about a new language or framework and decide to rewrite their code in it. They want to add a single new feature that would be easier to do in the new language. They could still do this in the old language, but it would take longer. So, they begin to rewrite. They get bored, and the project never gets finished or they are inexperienced, and the project takes much longer than anticipated to get up to the level of the original. It is an unacceptable delay in most cases. For new projects, use the appropriate languages, but rewrites for large businesses are often the nail in the coffin.
I completely agree that you should not worry about the NDA, but you should consult a lawyer nonetheless. jsavimbi is correct that the NDA is only going to bind you. As for the second point, I believe that you should not start with an indication of your value if you can help it, but you can provide revenue results. Your revenue now is not going to be your revenue in the future. As long as you are making anything, you are doing well. There is a big difference between $0 and $1. You should not disclose everything, though, until they provide you with more details, and let them make the first bids. As was said, this is the starting point of negotiations.
I agree with your comments that toolbars should respect the robots.txt because even if a human is doing the crawling, it is still an automated system that is indexing information from that site. I would not want toolbars attempting to send data back to Bing based on my queries on a company Intranet or a site that would normally not be indexed. Personal data entered into what the toolbar thought was a query field could be sent onward as well even if the robots.txt on the site restricted it. I think they should respect robots.txt in this case even if they are only monitoring user behavior.
I felt myself being urged to type on a non-existent keyboard as well. If it was a person near me at the keyboard, I would have felt compelled to tell them to move out of the chair and let me do the work.
To add to this, you would also be required to sign a non-compete agreement most likely that would prevent you from duplicating the site for some time period. The brand is something that you are not including in your price. Branding has not been seen as being very important, but even in the span of a year, there is a trust that can form in consumer relationships on the web.