Users and hosts-Newbe ?

[ampeloso]

Hello,
Can someone answer a few questions:

Some background:

Host table has 0 entries
User table has:
+-----------+------+
| Host | User |
+-----------+------+
| localhost | |
| % | |
| localhost | mike |
+-----------+------+

I thought I deleted the root, but the Processes shows :
+----+------+----------------+--------+---------+------+--------+-----------
------------+
| Id | User | Host | db | Command | Time | State | Info
|
+----+------+----------------+--------+---------+------+--------+-----------
------------+
| 15 | root | 127.0.0.1:1254 | mysql | Sleep | 243 | | [NULL]
|
| 27 | root | 127.0.0.1:1296 | [NULL] | Query | 0 | [NULL] | SHOW FULL
PROCESSLIST |
+----+------+----------------+--------+---------+------+--------+-----------
------------+

1. If there are no hosts than how can the user table have hosts?
2 If there is no root than why is the always one connected even after a
restart?
3. Whats a blank username?
4. Who is @%?

Many Thanks
Mike