| Abbreveation | | description |
| IDC | | I Don't Care |
| IDK | | I Don't Know |
| ILU | | I Love You |
| IC | | I See |
| ICQ | | I Seek you |
| IMHO | | In My Honest/Humble Opinion |
| IMO | | In My Opinion |
| IMOW | | In My Own Words |
| IOW | | In Other Words |
| IRL | | In Real Life |
| IYQ | | I like you |
| IMNSHO | | in my not so humble opinion |
| IOU | | I owe you |
| IUSS | | If you say so |
| IRC | | Internet Relay Chat |
| 411 | | Info |
| IAC | | In any case |
| IAE | | In any event |
| IAITS | | It's all in the subject |
| IANAC | | I am not a crook |
| IANAL | | I am not a lawyer |
| IBT | | In between technology |
| IBTD | | I beg to differ |
| ID10T | | Idiot |
| IEF | | It's esther's fault |
| IFAB | | I found a bug |
| IFU | | I fucked up |
| IGGP | | I gotta go pee |
| IIIO | | Intel inside, idiot outside |
| IIMAD | | If it makes any difference |
| IIRC | | If I remember correctly |
| IIWM | | If it were me |
| ILICISCOMK | | I laughed, I cried, I spat/spilt coffee/crumbs/coke over my keyboard |
| ILY | | I love you |
| IM | | Instant messaging |
| IMCO | | In my considered opinion |
| IMPE | | In my previous/personal experience |
| IMVHO | | In my very humble opinion |
| INMP | | It's not my problem |
| INPO | | In no particular order |
| IOH | | I'm outta here |
| IOTTMCO | | Intuitively obvious to the most casual observer |
| IPN | | I'm posting naked |
| ISS | | I said so |
| ITM | | In the money |
| IYKWIM | | If you know what i mean |
| IYO | | In your opinion |
| IYSS | | If you say so |
| IYSWIM | | If you see what I mean |
| I 1DR | | I Wonder |
| IANAE | | I Am Not an Expert |
| IAT | | I Am Tired |
| IBRB | | I Will Be Right Back |
| ICBW | | I Could Be Wrong |
| IDL | | Ideal |
| IDM | | It Does Not Matter |
| IGTP | | I Get The Point |
| IHAIM | | I Have Another Instant Message |
| IHNO | | I Have No Opinion |
| IHTFP | | I Have Truly Found Paradise |
| IIR | | If I Remember or If I Recall |
| IMS | | I Am Sorry |
| ISTM | | It Seems to Me |
| ISTR | | I Seem To Remember |
| ISWYM | | I See What You Mean |
| IUM | | If You Must |
| IYKWIMAI | | If You Know What I Mean And I Think You Do |
| IAYL | | In A While |
| IHTFP | | I Hate This Fucking Place |
