PostgreSQL limitations question

Hi All
I found PG limitations (http://www.postgresql.org/about/):

- Maximum Rows per Table - Unlimited
- Maximum Table Size - 32 TB

My question is:
how is it possible to *reach* unlimited rows in table?

I did a test:
1. Create Table:
CREATE TABLE test.limits("RowValue" text) WITH (OIDS=FALSE, FILLFACTOR=100);

2. Fill table (I used pgScript available in pgAdmin);
DECLARE @I;
SET @I = 0;
WHILE @I < 1000
BEGIN
INSERT INTO test.limits ("RowValue") VALUES (NULL);
SET @I = @I + 1;
END

3. do Vacuum full to be sure free space is removed
VACUUM FULL test.limits;

4. I checked table size:
SELECT * FROM pg_size_pretty(pg_relation_size('test.limits'::regclass));
and I realized table size is 32 kB.

I used pgstattupet extension (
http://www.postgresql.org/docs/9.1/static/pgstattuple.html) to check what
is going on:
SELECT * FROM pgstattuple('test.limits');
and I got:
table_len tuple_count tuple_len tuple_percent dead_tuple_count
dead_tuple_len dead_tuple_percent free_space free_percent 32768 1000 24000
73.24 0 0 0 4608 14.06

Did I missed something?
Is there a non storage cost data type?

I know that "storage requirement for a short string (up to 126 bytes) is 1
byte plus the actual string" (
http://www.postgresql.org/docs/9.1/static/datatype-character.html).

Regards,
Bartek