Would need to create an account on twackit or enter their Twitter credentials (or use OAuth).

User should be able to specify min, max, mean, median, sum, etc. for cases where there is more than one value on a day. The same function would apply to every day.

have a way for people to twack things as a group, (e.g my weight vs. other twackers' weights)

Maybe just use OAuth to authenticate against Twitter account?

Set a goal value that is indicated in the report graph

As described for drill down in the lunch scenario where multiple tags are used it would be useful to generate pivot tables on that data.

My case was to track my friends twitter usage by submitting the number of tweets and user per day and then charting or comparing in a table.

The @reply would include a link to the report. not sure how to handle multiple hashtags, just pick the first one?

It would be nice to be able to post tuples and have twackit parse the values and graph them indepenently. For example, if tracking gas mileage: number of gallons, price per gallon, and miles driven since last fill-up.

For example, if two people are tracking #weight, show both in same graph