The US-VISIT system, the new post-9/11 computerized system for tracking visitors to the U.S. add a new component "US Arrival" and has been implemented at  border Ports of Entry.  Nonimmigrants (visitors and those with working visas such as H-1B and L-1B) will no longer fill in the white paper I-94's.  Instead, border officials enter the I-94 data into the US-VISIT system and then print the I-94 (click here for a sample).   As in the past, the I-94 card will include the expiration date of the nonimmigrant category (that is, the date the before which the person must leave the U.S. or change or extend the nonimmigrant status.  The new I-94's will also add two dates on the bottom: (1) a date showing the last time the person entered through US-VISIT, and (2) a date after which the person will have to go to through US-VISIT again. 

The new I-94s will not be issued for those entering under the Visa Waiver Program, which will still involve the green I-94W with the ten extra questions on the back.

US-VISIT is designed to conduct two searches through the anti-terrorism and criminal history watchlists - one based on a name check, and another based the fingerprint check.

The following are exempt from US-VISIT:

bulletU.S. citizens
bulletU.S. legal permanent residents.
bulletCanadians except for those with E and K visas. 
Unlike people from other countries, Canadians are not normally fingerprinted or photographed or run through the watchlists (but they may be if the inspector has doubts or suspicions).
Even though Canadians in L, H, TN, and R-1 are exempt from US-VISIT, they are not exempt from having their I-94 printed through US Arrival.   It is important that Canadians in working status make sure that their occupation entered on the I-94 is correct, especially for TNs. The border officers have drop-down menus with the occupations listed, but some of the occupations are not yet listed.   Recently, for example, when a TN Systems Analyst sought to enter the U.S. the inspector prepared to print the I-94 with the designation of "Computer Scientist" because "Computer Systems Analyst" was not on the drop-down list.  With the assistance of a supervisor, the correction was made and the officer wrote in "Systems Analyst."

US VISIT also includes "optional queries" in several databases that the officer can conduct on anyone:

bulletNCIC - II
bulletSecondary (to check and see if the person has ever been sent to secondary - this section brings up comments - one example they used was "Seems agitated and nervous."
bulletAddress (to check on whether there is any negative information about the address the person provides)
bulletCrossing history (to show when the person last went through US-VISIT.)
US VISIT will also be used to track those who have overstayed their status.  The system is designed to exclude those people who have applied for an extension.
The next phase in the implementation of US VISIT will be registration upon the departure from the U.S. of all visitors and temporary workers.