Just in case any of the recent spate of bun fighters can't be bothered to check out The Terms And Conditions (which incidentally have not changed for some significant period of time) - the relevant clauses are clause 3 and 4 and are copied below for you;

# Diary entries must not publish details of individuals that may identify them (either in an online or real life fashion) unless the diary author has written permission from the individual that could be identified and can prove this to the DearDiary.Net... Administration. Such identities may be construed as (but not limited to) First and Last names, Names and Addresses and/or Names and Telephone numbers.
# Authors may not post defamatory entries that name, either by implication or explicitly, other diary authors. Such entries will be deleted without notice and repeated offences under this clause can result in any or all accounts held at Hamiko being removed and your permission to use the system revoked (see clause 10). There is no scope within this clause for determining 'who started it', as any diary entry that violates this clause will be subject to the remedial action already specified, regardless of 'who started it'.