Difference Between &"join&" And &"exists&"

hi,

what is the main difference of using join or using exists.

e.g.1.
select t1.id, t1.name from table1 t1
join table2 t2
t2.id = t1.id

join table3 t3
t2.id = t3.id

where
t1.name like '%something'

e.g.2.

select t1.id, t1.name from table t1

where t1.name like '%something'
and (select t2.id from table2 t2
join table3 t3
t2.id = t3.id)

what is the main difference and how does this impact on the output?

thanx